Hmm... they have updated the faq and Odegon might be right about that. I was taking my info from a Q&A awhile back this makes it sound like you can't access the extrea credits at all =/

Originally Posted by SWTOR

As a Free-to-Play player, is there a limit to the number of Credits I can save?

Yes, a Free-to-Play character has a limit of 200,000 Credits. Once your character reaches the maximum amount of Credits, any further Credits earned will be retained and visible on the Currency tab of your inventory (press [I] to open). Retained Credits are not automatically accessible.